The primary goal of this Program project is to use the rhesus macaque model to explore features of immune aging, in order to subsequently devise methods and vaccines to enhance immunity in elderly humans. The four proposed Projects focus on synergistically evaluating the age-related changes of immunity in vivo. Therefore, the monkey cohorts to be studied have been unified in a single plan so that the scientific goals of each of these projects is met using the same animals. This approach not only makes the most efficient use of the animal resource, but also allows full cross-correlation of the various immunologic features of senescence in each animal. The Animal Core, functioning within the Oregon National Primate Center, will be responsible for managing all of the rhesus macaque studies in this project, including: 1) their selection for study, 2) their housing and general husbandry, 3) their clinical management and manipulation, 4) specimen collection and processing, and 5) necropsy studies. The Core will interact closely with project leaders and project laboratory personnel to facilitate the accomplishment of the programmatic goals.